Fabrication of Multilayer Alternating Polymer-based Dielectric Composites with Superior Energy Storage Performance via Layer-by-layer Spraying Assembly
Experimental study demonstrates superior energy storage density and breakdown strength in multilayer polymer composites, indicating a scalable strategy for dielectric films.
Key Points
To simultaneously enhance the dielectric constant and breakdown strength of polymer-based dielectric composites for advanced pulsed power and power electronics applications.
Synthesized surface-modified fillers by covalently grafting carboxylated polyetherimide (CPEI) onto boron nitride nanosheets (BNNS) and barium strontium titanate (BST).
Fabricated 3-, 5-, and 7-layer alternating high-dielectric (CPEI@BST/PEI) and high-insulation (CPEI@BNNS/PEI) composite films via layer-by-layer spray assembly.
Evaluated dielectric properties, energy storage parameters, and breakdown dynamics using experimental characterization and numerical simulations.
The 7-layer composite film achieved a dielectric constant of 7.43 at 1 kHz and a breakdown strength of 731.2 kV·mm⁻¹.
The film attained a discharge energy density of 20.87 J·cm⁻³ (4.91-fold higher than pure PEI) while maintaining charge-discharge efficiency above 90%.
Alternating layers introduced deep-level interface traps that suppressed space charge migration, homogenized internal electric fields, and impeded electrical tree propagation.